Protective device



H c; 1.. ALLCUTT. .PROTECTIVE DEVICE.

APPLICATION FILED L29. 1917.

1,371,538. Patented Malt 15; 1921.

INVENTOR wm SES: MW Cfieszer T/W/C'Ufi' I ATTORNEY UNITED STATES PATENT OFFICE.

CHESTER T. ALLCUTT, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VAN IA.

Specification of Letters Patent.

PROTECTIVE DEVICE.

Patented Mar. 15, 1921.

Application filed. January 29, 1917. Serial No. 145,326.

To all whom it may concern:

Be it'known that I, CHESTER T. ALLoU'r'r, a citizen of the United States, and a resident of VVilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Protective Devices, of which the following is a specification.

My invention relates to protective devices andparticularly to devices for indicating when the temperature of the rotatable member of a dynamo-electric machine reaches a predetermined value.

The object of my invention is to provide a device of the above indicated character that shall be actuated by the centrifugal force of the rotatable member of the machine when the temperature of the rotatable member exceeds a predetermined value only.

In one form of my invention, I provide a receptacle that is disposed in the body portion of the rotatable member having a substance, such as an alloy of tin, bismuth and lead therein, which is adapted to become a fluid at a predetermined temperature. An alarm circuit is provided that is adapted to be closed when the substance is so displaced by the centrifugal force of the rotatable member'or armature that it bridges the terminals of the alarm circuit.

In the accompanying drawings, Figure 1 is a diagrammatic view of a temperatureprotective device embodying my invention, and Fig. 2 is a diagrammatic view of a modified form of protective device embodying my invention.

An armature or rotatable member 1 that is to be protected against excessive rises in temperature is mounted on a shaft 2 which is grounded. A conducting receptacle 3 is disposed within the body portion of the armature 1 and is provided with an insulating member 4 at one end thereof through which extends a terminal member 5. A

fusible substance 6, such as an alloy of tin,

audible or visible signal device, such as a bell 10, to the ground.

Since the substance 6 is normally retained out of engagement with the terminal 5, the circuit through the bell 10 is maintained in its open position. However, when the temperature of the armature 1 increases to such value that the substance 6 becomes a fluid,

the centrifugal force of the armature 1 will cause it to be displaced to such position that it will bridge the space between the terminal 5 and the conducting casing of the receptacle 3. This will complete a circuit through the bell 10 for the purpose of indicating that the temperature of the armature 1 has exceeded a predetermined value. lVhen the signal device indicates'that the temperature of the armature has exceeded a predetermined value, it is desirable to open the circuit and bring the armature to rest in substantially the position shown in Fig. 1 of the drawings. When the armature is brought to rest in this position, the substance 6 will assume its lowermost position and, when the temperature of the armature decreases to a predetermined value, it will solidify to preclude the completion of the circuit through the bell 10 until the temperature of the armature 1, when operating, again exceeds a predetermined value.

If it is not feasible to bring the armature 1 to rest in a predetermined position, I pro vide two receptacles 11 and 12, substantially as shown in Fig. 2 of the drawings, that are disposed in the body of the armature 1 at opposite sides thereof with respect to each other. The casing of the receptacle 11 is connected to the shaft 2, and the casing of the receptacle 12 is connected to the slip ring 7. The terminal 5 of the receptacle 11 is connected to the terminal 5 of the receptacle 12 and the collector brush 8 is connected to ground through the source 9 of. electromotive force and the trip coil 13 of a circuit interrupter 14:. The circuit interrupter 14 may be adapted to control a circuit 15 that may constitute the main feeder circuit of the machine to be protected.

By the use of the device shown in Fig. 2 of the drawings, it is immaterial in which position the armature 1 is brought to rest because the substance 6 must be in engagement with both of the terminals 5 before the trip coil 13 is energized. That is, the tem perature of the armature 1 must exceed a predetermined value and the armature 1 must be rotating at a predetermined speed in order to effect the tripping of the inter.- rupter l4. I

While I have shown my invention in its preferred forms, it will be understood that it is not so limited and that various modi fiCLt1OI1S may be made therein Without demature anda circuit ot a receptacle dis posed Within the armature and having a fusible substance therein that is adapted to ice dlsplaced by the movement of the armature only under predetermined conditions to i I tr o machine, of two receptacles disposed 1n complete the circuit.

- 2 A device. fora dynamo-electric ma -V chine comprising a receptacle disposed Within the rotatable member of the machine and having av fusible substance therein, and-a circuit, said fusible substance being" adapted .to complete the circuit only When the temperature of the movable member reaches a predetermlned value.

device for a dynamo-electric 1nachine comprising a receptacle disposed with in the armature of the machine and having fusible substance there1n,-and a clrcult,

said fusible substance .beingiadapted to be so displaced by the movement of the arma- Thecombination with a 'turefas to complete the circuit only when i the temperature of the armature reaches a predetermlned value.

v dynamo-electric machine, of tivo'receptacles disposed 111 ct the armature .toeffect a closure of the o electric circuit when the temperature of the armature exceeds a predetermined value.- 5. The comhmatlonfwlth a'dynamo-electhe rotatable member of'the machine atopposite sides thereof, andelectric circuit,

aid receptacles containing a fusibl substance that is adapted to be sodisplacjed und r predetermined conditions'thatthe electric circuit is rendered operat1ve.'

lutestimony whereof" I: have hereunto subscribed my name this lQth day 01 anu .ary, 1917; a V V Q ES'LER ALLCUTTQ I 

